Tebeitoey



(No Model.)

P. LEUBA`.

SBXTANT.

No. 310,692. PatentedJan. 13, 1885.

PHILIPPE LEUBA, OF BEAVER, UTAH TERRITORY.

SEXTANT.

SPECIFICATION forming part of Letters Patent No. 310,692, dated Januaryf3, 1885.

Application filed August 2. 1F82. Renewed August Q8, 1884. (No model.)

-tion of sextants in which there are two artiiicial horizons, one i'ortaking elevations and the other for taking depressions, and in whichprovision is made for use of the sextant in the dark or at night.

l Reference is to be had to the accompanying drawings, forming part ofthis specification, in which similar letters of reference indicatecorresponding parts in all the iigures.

Figure l represents a side view of a sextant having my improvementsapplied, and Fig. 2 a bottom edge view of the same. Fig. 3 is a diagramin illustration oi" the adjustment of one of the levels of theinstrument, to make the line ofy collimation horizontal.

A is the frame of the sextant, and B the arc, which should be graduated,as usual. C is the eye-piece; D E, duid-levels attached to the frame, soas to occupy positions at right angles with each other; G, thehorizon-glass, and H a reector. The level E is hinged, as at b, to admitof its adjustment either behind the horizon-glass G, as shown in fulllines in Figs. l and 2, or behind its support, as shown in dotted linesin Fig. 2-tl1at is to say, said level E is hinged to the frame A of thesextantin such manner that it may be folded back dat against the side ofthe frame when not required lor use. Vhcn in use its position is such asindicated in full lines, Figs. l and 2, so that it is in the properrelation with level D.

Then the instrument is in use for taking elevations, the level E isfolded behind its support, the instrument is held vertically, and sighttaken through the eye-piece C, to see in the reliector II the air-bubbleof the level D come to its level-mark, and to observe at the same timethe reflected image upon the horizoirglass G oi the point observed. Thereading upon the arc B then gives the angular distance of the pointobserved above the horizon-line.

To adjust the level D andcause the line of collimation, as required, toput the instrument in condition for accurate work to be horizontal, Ierect upon any suitable firm surface or support-such, for example, as asolid table or block, M, as shown in Fig` 3-two Wires,

d d, having their upper ends bent at right,

angles toward each other. The bent end of one of said wires is insertedin the hole of the eyepiece C, and the bent end of the other of the saidwires is inserted in a hole, e, of an adj usting-piece, I, when thesame, which is pivoted at f, is raised or swung into position for thepurpose. The instrument is then held with its plane in a verticalposition, and the level D adjusted by means ofits hinged connection gand adj usting-screw h.

To measure angles of depression, the level E is turned behind thehorizon-glass G, as shown `in iull lines in Figs. l`and 2. It is placedso that its air-bubble when at the level-point appears in full behindthe transparent half or portion t of the horizolrglass G as viewedthrough the eye-piece C. Having thus adjusted the instrument to use itfor measuring angles of depression, it is held so that its line ofcollimation S S will be vertical, the eye-piece G being uppermost andthe horizonglass G beneath. Sight is then taken down through theeye-piece to observe the air-bubble of the level E, behind the horizon`glass, and when it is at its level the reflection is noticed in thesilvered portion t' of the horizon-glass of the point observed. Theread` ing upon the arc B is the angle of depression which the observedpoint makes with the horizon-line.

'Io adj ust the level E, and to malte the line of collimation S S trulyvertical, the instrument is rst set by its handle (which is not hereshown) as nearly vertical as possible. I then place under it a saucer orother suitable vessel containing mercury, molasses, water, or othersuitable substance, and stretch a string across the edges ofsaidvvessel, and look through the eyepiece O in line or range with theedge of the silvered portion fi of the horizon-glass G to the string,after which I move the vessel (this being more convenient than to movethe sextant, which is held fixed in position) till the string covers itsimage in the substance contained within the saucer. The instrument isthen firmly secured, and the level E adjusted so that its air-bubblecomes IOL).

to its level, when the line of collimation S S will be truly vertical.To provide for such adjustment of the level E, it is pivoted, as at g,and tted with an adjusting-screw, 7L, as in the case of the level D.

To use the instrument at nighttime or in dark places, both levels D Eare uncovered or made open on their under sides, as shown at.

m for the level D in Fig. 2; Said under sides or backs of the levels arealso provided with slideways ma, designed to hold a plate which iscovered with luminous paint, and which will enable the observer to seethe air-bubble of the level and measure the angular distance of a sta-ror light from the horizon-line.

By the use of this my improved sextant an observer can always have ahorizon-line at his command, even in mountainous countries, withouthaving to carry with him avessel and liquid for an artificial horizon,and of setting the same up and of carefully removing it when changingthe point of observation. The horizon-line is always at hand Whether theobserver is on horseback, in a carriage, or in a boat on lakes andrivers. Moving away a few feet to obtain a better point of observationdoes not necessitate the moving of a liquid horizon every time a changeof place is desired, thus saving much time and trouble.

Having thus fully described my invention, I claim as new and desire tosecure by Letters Patent- 1. A sextant having duplicato attachedfluid-levcls D E, arranged in relation with each other, as described, incombination with the horizon-glass G, the reflector H, and the eye-pieceC, substantially as specified.

2. The combination of the hinged adjust ing-piece I, with thefluid-level D, the horizoirglass G, the reflector H, and the eyepiece C,essentially as specified.

3. A sextant having one or more attached fluid-levels made open at theirbacks, and constructed to receive Within such opening a plate having aluminous surface, substantially as and for the purpose herein described.

PHILIPPE LEUBA.

fitnessesz F. It. CLAYTON, D. LANG.

